(CNN) -- Rescue authorities reported all five people aboard a small sightseeing plane were killed when it crashed in a mountainous area of southeast Alaska on Tuesday, a Princess Cruises spokeswoman said.

The five included the plane's pilot and four Sun Princess cruise ship passengers, who were on the second day of a weeklong, round-trip cruise from Seattle, Washington, spokeswoman Julie Benson said in a statement.

The pilot sent out a distress signal late Tuesday afternoon while on a planned tour of Misty Fjords National Monument, south of Juneau near Ketchikan, Alaska, according to Benson.

When the single-engine DeHavilland Beaver did not return, "rescue helicopters were dispatched to the location of the flight seeing route," Benson said. "These helicopters subsequently spotted the float plane which ... crashed in rugged terrain."

No additional information was immediately released, but Benson said the company was working closely with local authorities to investigate the circumstances of the crash.

Meanwhile, Princess Cruises has permanently canceled all excursions with the tour company Taquan Air, operator of the plane, Benson said.

"We are devastated to report that our passengers and the plane's pilot perished in the accident," Benson said. "Our shoreside care team is doing everything possible to help their families through this difficult tragedy, and we share in their grief."